TRANSFER OF THIOSPHAERA-PANTOTROPHA TO PARACOCCUS-DENITRIFICANS

Comparative sequence analysis of in vitro-amplified 16S rRNA genes of Thiosphaera pantotropha GB17T(T = type strain) and Paracoccus denitrif icans LMG 4218T revealed identical 16S rRNA primary structures for the two organisms. The level of overall DNA similarity of Thiosphaera pan totropha GB17T and P. denitrificans DSM 65T is 85%, as determined by q uantitative DNA-DNA hybridization. Therefore, we propose the transfer of Thiosphaera pantotropha to P. denitrificans. The closest relative o f Thiosphaera pantotropha and P. denitrificans is Thiobacillus versutu s, as revealed by comparative 16S rRNA sequence analysis. These organi sms are members of the alpha subclass of the Proteobacteria. Within th is subclass, Thiosphaera pantotropha, P. denitrificans, and Thiobacill us versutus form a phylogenetic group with Rhodobacter sphaeroides, Rh odobacter capsulatus, and ''Erythrobacter longus.''